JPH05212806A - Method for producing three-dimensional object - Google Patents

Abstract

PURPOSE: To enable the cross section of an object to form a film of photohardenable composition containing a photoresponsive agent to be selectively irradiate to color or decolor and repeatedly integrating successive adjacent cross-sectional patterns of the object to enable the selected element to be independently colored. CONSTITUTION: A photochromic material of a colorless dye or optically bleachable dye which are colored by irradiation is mixed with a photohardenable composition. After scanning a single layer, the X-Y layer, to form a three- dimensional object for hardening, the layer is scanned or irradiated to color or bleach the selected parts of the layer. Those processes are repeated on a cross-sectional pattern to laminate the X-Y layer to color or bleach the selected areas of the three-dimensional object. The photochromic materials chosen so that the wave length is different from the irradiating wave length used i hardening the X-Y layer.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to the production of three-dimensional models from tomographic or CAD / CAM data. Here, the model contains one or more elements or parts, each element or part having a different color or unique texture, elasticity, or other tactile properties.

[0002]

BACKGROUND OF THE INVENTION Several methods and devices have been developed for producing three-dimensional objects or models by irradiating compositions that crosslink and solidify upon irradiation. U.S. Pat. Nos. 4,041,476 and 4,228,861 to Swainson disclose that an intersecting beam of radiation is used to independently solidify each point by scanning a volume to form a three-dimensional object. is doing. The Swainson method is complicated and expensive.

US Pat. No. 4,575,330 to Hull discloses a method of making a three-dimensional object by laminating successive thin layers of solidified photopolymerizable composition. This method became known as three-dimensional lithographic printing. In one embodiment described in this Hull patent, a three-dimensional object is provided with a thin layer of a photocurable composition on the surface of a platform immersed in a bath of the composition and using a laser beam to form this layer. Is formed by scanning. The laser is model X,
Control the Y dimension. The Z dimension is controlled by deepening the platform after each successive layer corresponding to the cross section of the model has polymerized or crosslinked.

Another method of making a three-dimensional object is described in US Pat. No. 4,940,412 by Blumental, in which a hard copy image having transparent and opaque portions is used to make a three-dimensional object. It is used as a mask in a photographic process for forming layers that are successively laminated and adhered.

Models prefabricated by the above method are essentially uniform in color and texture. It is desired to produce a model in which selected elements can be uniquely colored or contribute unique textures, elasticity, or other contact properties.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a three-dimensional object is produced which has uniquely colored elements or elements which have unique tactile properties. In a preferred embodiment of the invention, the three-dimensional object is produced by solid lithographic printing.

In one embodiment, the photoresponsive agent is
It is mixed with the photocurable composition. As each monolayer of the object is formed, the monolayer is irradiated by the photoresponsive agent to selectively add a photoresponsive agent that alters, bleaches, or colors the tactile properties of a portion of the model. To be scanned. Scanning for changes in color or tactile properties can be performed before, during, or after irradiation to form a monolayer.

In another embodiment of the invention, a combination of photobleachable photoinitiators is used to cure the photocurable layer. The irradiation used to cure the preselected portion of the model is selected based on the color desired in that model portion. That is, by selecting the irradiation that bleaches one of the photopolymerization initiators in the photocurable composition, the photocurable composition is free of radicals or other reactive groups generated by the bleached photopolymerization initiator. The photocuring initiator which is cured by the seed, while not bleached, is what colors the layer in the cured part. In other parts of the model where other colors are desired, the photocurable layer may be irradiated by irradiation to bleach other photoinitiators that cure the layer while the photoinitiator colors the layer. Hardened.

In another embodiment of the present invention, a substantially colorless color former is microencapsulated in a photodegradable composition or mixed with a photosoftenable composition to form microparticles. .. These agents are mixed with the photocurable composition. After or at the same time as the irradiation of the photocurable layer, the microcapsules or microparticles are selectively irradiated at the respective wavelengths that liberate, destroy or decompose the contained color former. It The color former reacts with the photopolymer or other agent in the composition to color the color former and to color a portion of the model. In another embodiment of the invention, inkjet or similar techniques are used to fix reactive or non-reactive dyes, optionally in the area of the cross-section layers. Here, color is applied so that the dye reacts or is trapped within the layer as the layer cures.

DEFINITIONS The term "feel characteristics" is used herein to refer to texture, resilience, elasticity.
city), hardness, etc.

The term "element" here means
By a part of the model such as a tumor in a model of the brain or a ligament in a model of the knee.

The term "XY layer" means herein a single layer or a single cross section of a three-dimensional object that is independently scanned, or illuminated, and laminated to form a three-dimensional object. To do.

[0013]

DETAILED DESCRIPTION OF THE INVENTION The present invention specifically describes its use in connection with three-dimensional lithographic printing, but it will be understood by those skilled in the art that this teaching translates into other methods of producing three-dimensional objects, such as those described in the aforementioned Blumental patent. Being used is
it is obvious.

The present invention also describes a method in which the color-limited or tactile-characteristic limited irradiation step is carried out after the cross-sectional pattern has been irradiated. It will be apparent to those skilled in the art that the former step can occur before, after, or simultaneously with the latter step.

According to one embodiment of the invention, a photochromic material is mixed with the photocurable composition. The photochromic material may be a colorless dye or a photobleachable dye that is colored by irradiation. After scanning to cure each XY layer, the layer is scanned or illuminated to color selected portions of the layer, and when the XY layers are stacked, the three-dimensional object is selected. The colored elements will be colored. In the three-dimensional lithographic printing process, layers are automatically laminated as the platform is lowered in the Z-dimension. In the Blumental method, the layers are laminated mechanically.

In the case of photocurable compositions containing photobleachable dyes, the XY layer is subsequently exposed to selected areas where color is not desired. In the case of photocolorants, the part of the XY layer where the color is desired is subsequently irradiated. Photochromic agents are not responsive to the radiation used to cure the XY layer. Also, when the layer cures, the agent becomes colored or bleached. Therefore, photochromic materials are selected that are sensitive at wavelengths different from the irradiation wavelengths used to cure the XY layer. In this way, colored elements can be formed in a three-dimensional object by subsequent irradiation of the part of the XY layer in which the color is desired or not desired.

Examples of photobleachable dyes useful in the above embodiments of the present invention are well known in the art and are incorporated by reference in US Patent Application No. 0, filed February 1, 1991.
7/649100, the merocyanine tra modification of benzospiropyran.
nsformations).

The photochromic agent is used in an amount having the desired color strength of the model. A typical photocurable composition can contain about 0.02 to 1 part of photochromic dye per 100 parts of monomer.

Examples of photocolorable dyes useful in the above embodiments are also well known in the art, and
US Patent Application No. 07/6 filed February 1, 991
Benzospiropyran described in No. 49100.

Another embodiment of the present invention utilizes diazo chemistry. The photocurable XY layer containing the monomer, diazo compound, and photoinitiator is irradiated with visible light to cure the portion corresponding to the solid portion of the three-dimensional object. After each XY layer is formed, the portions of the XY layer where color is not desired are illuminated with UV light. The XY layer is then treated with a treatment similar to that used in blueprints, namely ammonia vapor, to selectively color the unirradiated areas.

The diazo compounds useful in the embodiments of the present invention include compounds well known in the art and used in conventional blueprints. Ammonia gas treatment can be performed after irradiation in a room filled with ammonia gas.

According to another embodiment of the present invention, microcapsules or microparticles containing a color former or color precursor are prepared. The wall portion of the microcapsule is Japanese Patent Publication No. 52-3448.
8 (September 3, 1977) can be formed from photodegradable wall-forming polymers. Alternatively, the photo-softenable microparticles are described in US Pat. No. 4,788,
It can be formed from a photosoftening composition as described in No. 125. Alternatively, the color former can be microencapsulated by using a photodegradable agent that destroys the microcapsule wall, as described in Japanese Patent Publication 44-17733 (August 4, 1969). is there.
As described in the above-mentioned document, by mixing the color former with the light-sensitive microcapsules or the light-sensitive microparticles, the non-light-responsive color former becomes light-responsive. After the XY layer is cured, the microcapsules or microparticles are irradiated with actinic rays, whereby the wall portions of the microcapsules or microparticles are decomposed and the color former is released. In the case of a photochromic agent, the sensitivity of the microcapsules or microparticles is determined by the photocurable composition so that the color precursor can be selectively released independently of the curing of the XY layer. It is different from that of the thing.

In a particular embodiment of the present invention, the photocurable composition may contain multiple sets of microcapsules or microparticles that contain independently different color formers. For example, 3 of microcapsules or microparticles containing cyan, magenta and yellow color formers, respectively.
The set can be used to make a model with elements that are independently colored in a variety of different colors. For example, microcapsules or microparticles can be prepared by irradiation with different irradiation bands to decompose or soften. After curing the XY layer, cyan,
The magenta and yellow microcapsules or microparticles are selectively irradiated with different bands in selected parts of the XY layer so that the desired color is produced in the desired part of the XY layer. Done. For example,
In the portion of the XY layer within the element where yellow is desired, the layer is illuminated by irradiation that decomposes the yellow color former-containing microcapsules or microparticles. This part of the XY layer is not exposed to the radiation that decomposes the cyan-containing or magenta-containing microcapsules or microparticles. at the same time,
In those parts of the XY layer corresponding to the elements where red is desired, the layers are magenta-containing and yellow-containing, without irradiating these parts with irradiation that decomposes the cyan-containing microcapsules or microparticles. Irradiated with radiation that decomposes microcapsules or microparticles.

Color formers are essentially colorless compounds. Typically, they are colored by reacting with acids or bases. Therefore, in order to color the color former released from the microcapsules or microparticles, an acid or basic compound is added.
It must be mixed with the photocurable compound. Or
When the formed polymer is acidic or basic, it can function as a color former developer.

Useful examples of color formers are well known in the art and are described in US Pat. No. 4,399,209.

According to another embodiment of the invention, the photocurable composition contains a combination of two or more photobleachable photoinitiators. According to this embodiment, the XY layer is selectively colorable by subtracting color from the XY layer as it is formed. In this case, the XY layers are not uniformly exposed to the same wavelength of radiation to cure. Rather, each part of the layer is at a wavelength selected based on the color desired for the particular part of the XY layer,
Is irradiated. In this embodiment of the invention, a combination of cyan, magenta, and yellow photobleachable photoinitiators is used. These photopolymerization initiators bleach when polymerization is initiated. Some bleachable photoinitiators are those in which the polymerization produces an initiating radical intermediate and the photoinitiator loses color, reducing electron transfer (reducti).
ve electron transfer) (reference: Chesneau and Neck)
ers, J. Photochem, 42, 269 (19
88)).

A subtractive color separation model for forming a three-dimensional object in the reference color is thus possible. A monomer mixture is prepared containing cyan, magenta, and yellow photoinitiator dyes that are bleached once the photopolymer is formed. These absorptions must be carefully combined to be individually activated and bleachable. Onset occurs by irradiation tuned to cyan, magenta, or yellow absorption wavelengths. The computer input controls the wavelength, power and duration of the irradiation process, which controls not only the XY layer formation but also the color of each part. For example, if the initiation is caused by a yellow absorbing photoinitiator, polymer formation produces a blue object at this point. If the initiation is triggered by a magenta photoinitiator, polymer formation produces a green object at this point. If the initiation is caused by a cyan absorbing dye, this part is orange.

Examples of photoinitiators useful in this embodiment of the present invention include the diborate photoinitiators described in US Pat. No. 4,772,541, pending US patent filed May 20, 1991. Included are the fluorones described in application 07/702886 and the benzospiropyrans described in US patent application 07/649100, filed February 1, 1991.

In another embodiment of the invention, selected portions or elements of the model can be colored, such as by selectively reacting a polymer with a dye, at the point where color is desired. In some cases, the polymer is polymerized by techniques similar to the selective attachment of colored monomers to those portions of the XY layer where color is desired, or by using inkjet. The reactive colored monomer, such as rose bengal acrylate, eg, the acrylate ester of 3-hydroxy rose bengal, is then allowed to react with the polymer. That is, by attaching a reactive dye to the XY layers in those portions of the XY layer where a color is desired and irradiating the layer immediately after the dye is attached, the dye is in the attached portions. Kick X
-Fix to Y layer. Alternatively, the non-reactive dye can be applied to the layer in a similar fashion prior to curing the XY layer. Subsequent polymerisation of the XY layer retains the dye,
It produces the desired color. The use of non-reactive dyes is compatible with forming three-dimensional objects using the Blumental process, but problems of bleeding or spreading can occur in the three-dimensional lithographic process. Here, when the platform is lowered in the Z direction, the XY layer is then immersed in the photocurable composition.

Examples of other reactive dyes that can be used in embodiments of the present invention include dyes modified to contain vinyl groups. Examples of non-reactive dyes are
It is readily available in the art.

From the viewpoint of producing a selective color, the composition of the photocurable composition is not particularly important. Examples of monomers, oligomers, and photoinitiators useful in photocurable compositions are disclosed in DuPont EP 0393672 and Hull US Pat. No. 4,575,330.

According to a further embodiment of the invention, the tactile properties of the selected part of the three-dimensional model are altered. According to this embodiment of the invention, the degree of crosslinking is XY
It increases in selected portions of the layer, creating a texture difference. One of the main applications of the invention is the production of three-dimensional anatomical models. In these models,
It is desirable to change the tactile properties of some parts of the model to mimic the different feels, textures, or elasticity of various anatomical features. For example, in the manufacture of a model of the knee, it is desirable to form highly crosslinked, essentially inelastic polymer bones and to form a braid from a more elastic polymer.

One technique for imparting different tactile properties to the model is to illuminate the XY layer to form the first level of cross-linking in the polymer forming the layer. Further crosslinks are then introduced into selected portions of the layer by further irradiation. Also, differences in the degree of crosslinking, which result in different tactile properties, can be created by adjusting the intensity of the laser beam as the XY layer is scanned.

The chemistries that can be used to form different textures while adjusting the degree of cross-linking are based on oxime acrylates and are described in Kumar, G. et al.
S. , And Neckers, D.M. C. , "Lase
r-induced Three Dimensiona
l Photopolymerization Usi
ng Visible Initiators and
UV Cross-Linking by Photo
ossitive Monomers ”Macr
OMOLECULES Vol. 24, No. 15, p
4322 (1991)). Oxime acrylate has an absorption maximum in the UV range. This document refers to a high pressure mercury lamp or He-CdUV
A study of photocrosslinking of pendant groups using a laser and photopolymerization of oxime acrylate with a visible polymerization initiator using an argon ion laser is disclosed. Thus, the XY laser in this embodiment can be polymerized by scanning with a visible light laser and the second scan with a UV laser can be used to change the degree of crosslinking and create a texture difference. Is.

Although the present invention has been described in detail with reference to the embodiments, various conversions can be made by those skilled in the art without departing from the scope of the invention described in the appended claims. It will be clear that it is possible.

Claims (11)

[Claims] 1. A method of manufacturing a three-dimensional object having selected elements that are colored differently from other elements, comprising: a. Providing a film of a photocurable composition containing a photoresponsive agent, b. Illuminating the film in a cross-sectional pattern of the object to be formed, c. One or more portions of the cross-sectional pattern corresponding to the selected elements to be colored differently are selectively illuminated with radiation that activates the photoresponsive agent, wherein the light is A responsive agent colors or bleaches selected irradiated portions of the cross-sectional pattern, or decolorizes selected irradiation portions of the cross-sectional pattern, d. Repeating steps a, b, and c to form successive adjacent cross-sectional patterns of the object, e. A method of manufacturing a three-dimensional object, comprising providing the object by integrating the cross-sectional patterns. 2. The photoresponsive agent is a photobleaching dye.
The method according to claim 1. 3. The method according to claim 1, wherein the photoresponsive agent is a color precursor microencapsulated in a photodegradable wall-forming polymer. 4. The method according to claim 1, wherein the photoresponsive agent is photosoftening microparticles containing a color precursor. 5. The photocurable composition contains a plurality of photoresponsive agents, each photoresponsive agent having a different color so that selected portions of the object can be colored differently. The method according to claim 1, wherein formation control is performed. 6. The method of claim 1, wherein step c is performed after step b. 7. The method of claim 1 wherein step c is performed concurrently with step b. 8. The method according to claim 7, wherein the photoresponsive agent is a photobleaching photopolymerization initiator. 9. A method of manufacturing a three-dimensional object having selected elements that is colored differently from other elements, comprising: a. Providing a film of a photocurable composition, b. Illuminating the film in a cross-sectional pattern of the object to be formed, c. Attaching a dye to one or more portions of the cross-sectional pattern corresponding to the selected elements to be colored differently, d. Repeating steps a, b, and c to form successive adjacent cross-sectional patterns of the object, e. A method of manufacturing a three-dimensional object, which comprises integrating the cross-sectional patterns to provide the object, wherein the step c is performed before or after the step b. 10. The method of claim 9 wherein the dye is capable of reacting with the photocurable composition, thereby fixing the dye in the photocurable composition. 11. A method of manufacturing a three-dimensional object having selected elements having different tactile properties than other elements, comprising: a. Providing a film of a photocurable composition containing a photoresponsive agent capable of altering the tactile properties, b. Illuminating the film in a cross-sectional pattern of the object to be formed, c. Irradiation that activates the photoresponsive agent selectively irradiates one or more portions of the cross-sectional pattern corresponding to the selected element, where different tactile properties are desired, to the selected Changing the feel characteristics of the part, d. Repeating steps a, b, and c to form successive adjacent cross-sectional patterns of the object, e. A method of manufacturing a three-dimensional object, comprising providing the object by integrating the cross-sectional patterns.